msm: watchdog: Add reboot/shutdown notifications to watchdog

On shutdown or reboot path, callee CPU waits for one second
in order for other CPUs to respond. However, this coincides
with watchdog pet to bark timeout value, which sometimes
results in unnecessary watchdog barks.

Since we are either shutting down or rebooting the machine
anyways, we might as well wait a bit longer for bark timeout.
This gives a better chance to a graceful shutdown or reboot the
system because their call-sites are race prone.

Change-Id: Ie82f16dcc7671ddc05bf6c6ea20aa71981607273
Signed-off-by: Jay Chokshi <jchokshi@codeaurora.org>